Magnesium: what it is needed for, how much to take and which to choose
Magnesium is one of the most popular mineral supplements. It is chosen by people who feel tired, people who exercise and those who suffer from cramps.
In this article, you will learn what magnesium is needed for, how much you need per day, how the different forms of magnesium differ and why it is important not to exceed the supplement dose.
In brief. Magnesium contributes to the reduction of tiredness and fatigue, normal muscle function and normal functioning of the nervous system.1 Adults need about 300–350 mg per day, most of which comes from food.2 It is not recommended to take more than 250 mg of magnesium per day from supplements.3
What is magnesium needed for?
Magnesium contributes to:1
- the reduction of tiredness and fatigue;
- normal muscle function;
- normal functioning of the nervous system and normal psychological function;
- normal energy-yielding metabolism;
- the maintenance of normal bones and teeth.
How much magnesium do you need per day?
| Who | Amount per day | What it means for you |
|---|---|---|
| Men | 350 mg2 | From food and supplements combined. |
| Women | 300 mg2 | Including pregnant and breastfeeding women. |
| Limit for magnesium from supplements | 250 mg3 | Magnesium from food does not count towards this limit. |
Why is the limit for supplements lower than the requirement? Because magnesium from supplements can have a laxative effect in larger amounts, whereas magnesium from food does not.3
Where is magnesium found?
Nuts, pumpkin and other seeds, legumes, wholegrain products, dark green leafy vegetables and cocoa are rich in magnesium.4 If you eat these foods every day, you may not need a magnesium supplement.
Example. A handful of almonds with breakfast and lentil soup for lunch is a simple way to get more magnesium without supplements.
Which form of magnesium should you choose?
The most important thing is to find the amount of magnesium itself on the label, not the amount of the compound. For example, 2000 mg of magnesium bisglycinate contains only about 200 mg of magnesium.
| Form | What to know |
|---|---|
| Citrate | Well absorbed.4 Higher doses can have a laxative effect. |
| Glycinate (bisglycinate) | Often chosen if citrate causes digestive discomfort. |
| Malate, taurate | Less studied forms. The amount of magnesium is still what matters most. |
| Oxide | A lot of magnesium in a single tablet, but less well absorbed.4 |
Add up the amounts. If you take a 200 mg magnesium supplement and a multivitamin with 100 mg of magnesium, you are already getting 300 mg from supplements – more than the recommended limit.
Does magnesium help with cramps and sleep problems?
Cramps. Magnesium contributes to normal muscle function.¹ However, in studies of older people who frequently suffer from leg cramps, it did not significantly reduce cramps.⁵ If cramps keep recurring, consult a doctor.
Sleep. Magnesium contributes to normal functioning of the nervous system.¹ Scientists are also studying its link with sleep, but so far the results are mixed.⁶ An evening magnesium supplement can be part of a calm evening, but it is worth establishing a regular sleep routine first.
When should you be careful?
- You have kidney disease – take magnesium supplements only with your doctor's approval.4
- You are taking antibiotics (tetracyclines, quinolones) or osteoporosis medicines (bisphosphonates) – take magnesium at a different time. Discuss the interval with your pharmacist.4
- You develop diarrhoea – reduce the dose or choose a different form.3
Selected magnesium products
Commercial information. The products listed here are available in our shop. This is not an effectiveness ranking. Before buying, check the ingredients and directions for use on the product page.
Magnesium Glycinate - 180 tablets - NOW Foods
Magnesium bisglycinate, 200 mg of magnesium per two tablets. The manufacturer recommends 2 tablets 1–2 times a day, but taking them twice a day exceeds the 250 mg limit.7
Magnesium Citrate - 250 Capsules - Swanson
Magnesium citrate, 225 mg of magnesium per two tablets. The manufacturer recommends 2 tablets 1–2 times a day. To stay within the 250 mg limit, one serving is enough.8
Magnesium Malate Caps - 180 vcaps - NOW Foods
Magnesium malate, 95 mg of magnesium per capsule, taken as 1 capsule a day with a meal. The low dose is convenient if you also get magnesium from food or multivitamins.9
Magnesium Taurate - 100 mg - 120 capsules - Swanson
Magnesium taurate, 200 mg of magnesium per two tablets, taken once a day. The 100 mg stated in the name is the amount per tablet.10
Frequently asked questions
When is the best time to take magnesium?
The timing does not matter. It is most convenient to take it with a meal, as digestive discomfort is then less likely. If you take a higher dose, you can split it into two parts.
Do people who exercise need more magnesium?
Some magnesium is lost through sweat, but a varied diet usually replaces it. Read more about supplements for people who exercise in the article Supplements for people who exercise.
How can I tell if I am lacking magnesium?
A mild deficiency often causes no symptoms at all.4 If you experience persistent tiredness or muscle weakness, consult a doctor.
Scientific sources
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (consolidated version). EUR-Lex
- EFSA NDA Panel. Scientific opinion on dietary reference values for magnesium. EFSA Journal. 2015;13(7):4186. doi:10.2903/j.efsa.2015.4186
- Scientific Committee on Food, EFSA. Tolerable upper intake levels for vitamins and minerals. 2006. efsa.europa.eu
- NIH Office of Dietary Supplements. Magnesium – Fact Sheet for Health Professionals. ods.od.nih.gov
- Garrison SR, Korownyk CS, Kolber MR et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9:CD009402. doi:10.1002/14651858.CD009402.pub3
- Arab A, Rafie N, Amani R, Shirani F. The role of magnesium in sleep health: a systematic review of available literature. Biol Trace Elem Res. 2023;201(1):121–128. doi:10.1007/s12011-022-03162-1
- NOW Foods. Magnesium Glycinate, 180 tablets. Product label.
- Swanson. Magnesium Citrate, 240 tablets. Product label.
- NOW Foods. Magnesium Malate Caps, 180 capsules. Product label.
- Swanson. Magnesium Taurate, 100 mg, 120 tablets. Product label.
Disclaimer. This article is for information purposes only and does not replace consultation with a doctor or pharmacist. Food supplements are not intended to treat or prevent diseases and do not replace a varied diet and a healthy lifestyle. Before taking supplements, especially during pregnancy or breastfeeding, if you have a chronic condition or if you are taking medicines, consult a healthcare professional.
